Propeller



SEMI. 29, lgl. v Q PEMSL 1,825,473

PROPELLER Filed Sept. l7 1950 Patented Sept. 29, 1931 GEORGE PEMSL, 01E' DUBUQUE, IUWA PROPJELLER nlipplimion filed. september i7, 193e. seriall No. 482,408.

simple and inexpensive construction, yet durable and eflicient in operation.

These and other objects and advantages of my invention will become more fully l known as the description proceeds and will then be specifically defined in `thev appended claim.

In the accompanying drawings forming a material part of this disclosure: y

Fig. 1 shows an aerial propeller in elevation constructed according to my invention.

Fig. 2 is an edge view of the same.

Fig. 3 is a cross-section on line 3-3 of Figure l.

Fig. 4 is a fragmentary inner edge view of the propeller partly in section on line 4-4 of Figure l.

As illustrated the obliquely curved propeller blades l0 and 11 of substantially elliptical 30 outlines are made integrally and have a median boss 12 provided with an opening 13 for the shaft from which the blades are torsionally extending to both sides. l

VThe inner face of the blade ris fluted as 35 indicatedat 14 to present an air engaging face and shoulder 15 and a thrust end surface 16 while shoulder 15 is decreasing in width from the center towards thrust member 16.

In a similar `manner the outer face of blade 11 is luted or chamfered, as at 17` to present an air engaging shoulder 18 and a thrust end surface 19.

In operation the air willbe `engaged by the shoulders, 15, 18, during the rapid rotation of the propeller and thus the propeller blades i will develop a driving force superior to all the -known propellers, the greater number of whichl allows the air to flow smoothly over the propeller blades, thus losing 'a eat amount of their driving power. The tiust surfaces engaging the air and forcing it gradually against the shoulders towards the center of the propeller.

It will be understood that I have described and shown one form of my new and improved `aerial propeller as an example only, and that `I may make such changes in the construction of the-minor details thereof as come within the scope of the appended claim without departure from the spirit of my invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

An aerial propeller comprising asubstantially S-shaped body of equal width through 55 out, a perforated median boss, a pair of blades extending torsionally to both sides of said boss, the inner face of one of theblades fluted to presentan air engaging face and shoulder decreasing in width from the boss towards the end of the blade, the outer face of the other blade fluted to present anl air engaging shoulder facing in a direction opposite to the inner face of the first-named blade, and com,- paratively wide thrust-surfaces formed at w the ends of the blades for gradually forcing the air against the shoulders towards the center of the propeller.

In. witness whereof I have signed my name to this specification.

GEORGE PEMSL 

